1. Field of the Invention
The invention generally relates to systems and methods for artificially supplementing the function of a sphincter muscle in a patient. More specifically, the invention relates to systems and methods for supplementing the function of the sphincter muscle by changing the viscosity state of fluid within a collar that encircles a portion of an anatomical conduit controlled by the sphincter muscle.
2. Discussion of the Related Art
Control of urinary continence depends on the function of the sphincter muscle straddling the urethra of a person. Ideally, the sphincter muscle squeezes the urethra to stop the flow of urine from the bladder and relaxes to open the passageway of the urethra when elimination of urine from the bladder through the urethra is desired. Over time, the function of the anatomical sphincter muscles can become damaged, weakened, or otherwise impaired such that the sphincter muscle is partially or completely unable to squeeze the urethra sufficiently to prevent unintended flowing of fluids from the bladder. As a result, incontinence may occur. Artificial sphincters have been developed to treat incontinence in persons having weakened or otherwise impaired sphincter muscles.
FIG. 1 shows an exemplary conventional artificial sphincter control system. The system shown in FIG. 1 comprises a cuff 10, a pump 20, a balloon reservoir 30 and tubing 40 connecting the various components to one another. Such artificial sphincters are typically surgically implanted in a patient through incisions in the lower abdomen and labia for females, and in the abdomen, scrotum, and between the scrotum and anus for males. FIG. 2 illustrates such a conventional device implanted in a male.
As shown in FIG. 2, the cuff 10 surrounds a portion of the urethra U, the pump 10 is placed within the scrotum S, and the balloon reservoir 30 is placed in the lower abdomen A. Tubes 40 connect the various components. In practice, the conventional cuff 10 is inflated using fluid from the balloon reservoir 30. The inflated cuff 10 squeezes that portion of the urethra U that is surrounded with the cuff. The inflated cuff 10 squeezes the urethra closed and thus stops urine from flowing from the bladder B through the urethra.
The pump 20, placed within the scrotum S as shown in FIG. 2, controls the movement of fluid to and from the cuff 10 and the balloon reservoir 30. For example, manually pressing the pump 20 deflates the cuff 10 by displacing fluid from the cuff 10 to the balloon reservoir 30. When the cuff 10 is deflated, the urethra is opened and urine is able to pass there-through for elimination from the body. After a designated time period has passed, for example, 2-3 minutes, fluid automatically leaves the balloon reservoir 30 and returns to the cuff 10 to inflate the cuff 10 once again. As before, when the cuff 10 is fully inflated, the urethra is generally squeezed closed and urine does not pass there-through.
Although the systems and methods of known artificial sphincters, such as those described above, offer supplemental function to a compromised sphincter muscle, the placement of the pump in the labia or scrotum of an individual can interfere with other physical activities. Moreover, inadequate emptying of the bladder may occur if the cuff 10 becomes re-inflated too quickly, as might occur when the pump 10 is insufficiently depressed such that only small amounts of fluid are displaced from the cuff 10 to the balloon reservoir 30. Still further, the network of artificial conduits connecting the pump, the collar and the balloon reservoir of conventional systems is subject to infection and/or stoppages that can render the device unreliable. Such problems are often only remedied by additional surgeries.
In view of the above, a need exists for systems and methods that simplify and render more reliable the supplemental control of an anatomical sphincter muscle.